Phenologyshiftsandrangeexpansionscauseorganismstoexperiencenoveldaylength-temperaturecorrelations.Dependingonthetemporalniche,organismsmaybenefitorsufferfromchangesindaylength,thuspotentiallyaffectingphenologicaladaptation.WeassessedtheimpactofdaylengthchangesonlarvaeofChrysoperlacarnea(Stephens)andEpisyrphusbalteatus(DeGeer),bothofwhichpreyonaphids.LarvaeofE.balteatusarenight-active,whereasthoseofC.carneaappeartobecrepuscular.Wesubjectedbothspeciesinclimatechamberstodaylengthsof16:8L:Dand,tocircumventdiapauseresponses,20:4L:D.Werecordeddevelopmenttimesandpredationratesofbothspecies.E.balteatusgrew13%fasterinthe16:8L:Dtreatmentandpreyedonsignificantlymoreaphids.Incontrast,C.carneagrew13%fasterinthe20:4L:Dtreatmentandhigherpredationratesin20:4L:Dweremarginallysignificant.Ourresultsshowthatdaylengthaffectsdevelopmentandpredation,butthatthedirectiondependsonspecies.Suchdifferencesintheuseofdaylengthmayaltertheefficiencyofbiocontrolagentsinachangingclimate.
